In the related art, with respect to crockery such as a toilet bowl and a washstand which are installed at a water-using site in a building, and the like, various kinds of surface treatments are performed to make washing of a surface contaminant easy. Recently, in a contaminant, an oily component has been increased due to an effect of westernization in a dietary life of human beings, and thus it is difficult to sufficiently wash a contaminant from a surface of the crockery.
Although not intended to wash a surface, Patent Document 1 discloses a method in which a surface of a material mainly containing silicon oxide is treated with a silane coupling agent, and then a reactive surfactant, which has a reactive group such as an acryloyl group or a vinyl group in the middle of a side chain or a hydrophobic group, is allowed to react with the surface so as to give an anti-fog property, an antifouling property, and the like to a glass product. Patent Document 1 also discloses a specific compound in the method.
Patent Document 2 discloses a composition that contains a silane coupling agent that includes an epoxy group and an isocyanate group, a hydrophilic polymer having a functional group that is allowed to react with the epoxy group and the isocyanate group, and a hydrophilic group such as potassium sulphonate, and an alkoxide compound such as tetraalkoxysilane, and the like so as to form a hydrophilic film excellent in the antifouling property and abrasion resistance on a surface of a base material such as a glass plate.